检索结果-南通市图书馆

Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central Chinese Loess Plateau

引用

Chinese science Bulletin 2007年第17期52卷 2407-2412页

作者： DU XueQing1,6, WANG YongHong2, REN JianGuo3, YE XianRen4 & LU HuaYu5,1 1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of sciences, Xi’an 710075, china 2 College of Marine Geosciences, Ocean University of china, Qingdao 266003, china 3 national natural science foundation of china, beijing 100085, china 4 Lanzhou Research Center for Petroleum and natural Gas Resources, Institute of Geology and Geophysics, Chinese Academy of sciences, Lanzhou 730000, china 5 Key Laboratory of Coast and Island Development, School of Geographic and Oceanographic sciences, Nanjing University, Nanjing 210093, china 6 Graduate University of Chinese Academy of sciences, beijing 100049, china State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China Graduate University of Chinese Academy of sciences Beijing 100049 China College of Marine Geosciences Ocean University of China Qingdao 266003 China national natural science foundation of china Beijing 100085 China Lanzhou Research Center for Petroleum and natural Gas Resources Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China Key Laboratory of Coast and Island Development School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planet... 详细信息

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus 3 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planetary dust particles (IDPs), which are very rich in 3He, continuously bombard the Earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the Earth surface sediments. Since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concen- tration and helium isotopic ratio. Results show that the 3He/4He ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4He ratio of the extracted magnetic substances is also higher than that of the average level of the Earth’s crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

关键词：中国黄土高原古土壤氦同位素行星际尘埃颗粒反方向磁化

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Asymptotic behavior of the shock solution for a class of nonlinear equations

引用

Progress in natural science:Materials International 2003年第10期 48-50页

作者： MO Jiaqi 1*, ZHU Jiang 2 and WANG Hui 3(1. Department of Mathemtics, Anhui Normal University, Wuhu 241000, china 2. ICEES, Institute of Atmospheric Physics, Chinese Academy of sciences, beijing 100029, china 3. national natural science foundation of china, beijing 100085, china) Department of Mathemtics Anhui Normal University Wuhu 241000 China ICEES Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China national natural science foundation of china Beijing 100085 China

The high precision approximation of the shock solution for a class of nonlinear problems is obtained using a simple method.

关键词： nonlinear equation shock boundary layer.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

General expressions of peaked traveling wave solutions of CH-γ and CH equations

引用

science china Mathematics 2004年第6期47卷 862-873页

作者： ZHANG WenlingDepartment of Mathematics and Physics, national natural science foundation of china, beijing 100085, china Department of Mathematics and Physics National Natural Science Foundation of China Beijing China

We use qualitative analysis and numerical simulation to study peaked traveling wave solutions of CH-γ and CH equations. General expressions of peakon and periodic cusp wave solutions are obtained. Some previous resul... 详细信息

关键词： peaked traveling waves general expressions numerical simulations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

International symposium on communications and information technologies 2005 proceedings (ISCIT 2005) October 12-14, 2005, beijing, china sponsored by The national natural science foundation of Chi

引用

2005年

作者： sponsored by The national natural science foundation of china ...[et al] [editor-in-chief: Zheng Zhou].

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

A survey on routing in wireless sensor networks

引用

Progress in natural science:Materials International 2007年第3期17卷 261-269页

作者： XIAO Renyi and WU Guozheng (Department of Information sciences, national natural science foundation of china, beijing 100085, china) Department of Information sciences National Natural Science Foundation of China Beijing 100085 China

One of the most important issues in wireless sensor networks is data delivery service between sensors and the data collection unit (called sink). Although sensor networks and mobile ad hoc networks are similar to some extent, they are radically distinct in many aspects. Sensor networks have many unique features, making them more challenging and need further research efforts. The existing routing protocols for sensor networks can be classified as indicator-based and indicator-free. In this survey, we make a comparative study of these protocols. Open issues and research directions are pointed out as guidelines for our future work.

关键词： sensor network distributed system routing ad-hoc network.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

WJG sets an example of internationalization for other Chinese academic journals

引用

World Journal of Gastroenterology 2010年第22期16卷 2707-2709页

作者： Guang-An Zu, Department of Publication, national natural science foundation of china, beijing 100085, china Department of Publication National Natural Science Foundation of China Beijing 100085

Supported by the "Special Fund for Key Academic Journals" of the national natural science foundation of china, World Journal of Gastroenterology (WJG ) has become a high-impact international clinical medical journal due to the great efforts of Professor LianSheng Ma, Editor-in-Chief, and his team over several years. Now, WJG has successfully achieved a high degree of internationalization and sets a good example for other Chinese academic journals.

关键词： china Academic journals Internationalization

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Prediction of Enthalpies of Fusion for Divalent Rare Earth Halides Based on Modeling by Artificial Neural Networks and Pattern Recognition

引用

International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 24-26页

作者： Yimin Sun Zhiyu Qiao Minghong He(Applied science School, University of science & Technology beijing, beijing 100083, china)(national natural science foundation of china, beijing 100083, china) Applied science School University of Science and Technology Beijing Beijing 100083 China national natural science foundation of china Beijing 100083 China

The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius and electronegativity. The model,represented by a back-propagation netal network, was trained with a 12 set of published data for divalent rare earth halides and then was used to predict the unknown ones. Also the criterion equations were ptesented to determine the enthalpies of fuSion for divalent rare earth halides using pattern recognition in mis work. The results from the model in ANN and criterion equations are in very good agreement with reference data.

关键词： BP neural network pattern recognition enthalpy of fusion divalent rare earth halides microstructural parameters

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

FUTURE OF HIGH TEMPERATURE MATERIALS FOR GAS TURBINE

引用

Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 391-406页

作者： C.X. Shi(national natural science foundation of china, beijing 100083, china )

A comprehensive survey was made of various candidate high temperature materials for gas turbine use, and their relative merits and drawbacks were assessed. It is shown that superalloys, fine-tuned, will be persistent for the next few decades, to be followed up by high temperature intermetallics. For advanced ceramics, the problems of reliability and cost will have to be solved before they can be used in critical parts of *** are C/C composites with their oxidation problem. Surface modification and development of thermal barrier coatings can effectively overcome many problems of gas turbine materials and these technologies should be emphasized.

关键词： superalloy intermetallic compound ceramic C/C composite,surface modification

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Identification of the Angel -related elements in cyprinid fishes and their phylogenetic implications

引用

Progress in natural science:Materials International 2007年第2期17卷 168-171页

作者： WANG Li, HE Shunping and CHEN Yiyu ( Institute of Hydrobiology, Chinese Academy of sciences, Wuhan 430072, china Graduate School of the Chinese Academy of sciences, beijing 100039, china national natural science foundation of china, beijing 100085, china) Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China. Graduate School of Chinese Academy of sciences Beijing 100039 China. national natural science foundation of china Beijing 100085 China

Angel-related element belongs to the family of miniature inverted-repeat transposable elements (MITEs). In this paper we report the identification of an Angel- related element in the series Leuciscini of cyprinid fishes, which is located in the second intron of the growth hormone (GH) gene. We have also found that this element is absent in orthologous locus in the series Barbini of cyprinid fishes, that provides new evidence for the monophyly of the series Leuciscini. The insertion of Angel -related element into the GH gene might take place in the common ancestor of the series Leuciscini after its divergence from the series Barbini. The high sequence divergence and relatively broad species distribution of Angel-related elements implies that they might be ancient transposons which appeared about 26 million years ago.

关键词： Angel -related elements the series Leuciscini monophyly.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

ON SYMMETRIC SCALAR CURVAURE ON S^2

引用

Chinese Annals of Mathematics,Series B 1999年第3期20卷 325-330页

作者： JI MIN(Graduate School at beijing, University of science and Technology of china, beijing 100039, china.)(Project supported by the national natural science foundation of china (No.19631050, No.19725102)and the foundation of the Ministry of Education of Ch Graduate School at beijing University of Science and Technology of China Beijing 100039 China

Some new results are obtained for the problem of prescribing scalar curvature R on S2 when R possesses some kinds of symmetries.

关键词： Scalar curvature Symmetry Critical point Minimax method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：